BACKGROUND AND PURPOSE:

• BNT162b2 (Pfizer/BioNTech) COVID-19 vaccine was shown to be 95% effective at preventing COVID-19
• Several COVID-19 variants have been detected in recent months
  • South Africa variant: B.1.351
  • UK variant: B.1.1.7
  • Brazil variant: P.1
• Lustig et al. (NEJM Correspondence, 2021) investigated whether one dose of the BNT162b2 vaccine would increase neutralizing activity against the B.1.1.7, B.1.351, and P.1 variants in people previously infected with SARS-CoV-2

METHODS:

• Microneutralization assay
• Population
  • Healthcare workers
  • Previously infected with the original SARS-CoV-2
• Study design
  • All participants were given a single dose of the BNT162b2 vaccine
  • Serum samples were obtained
    • 1 to 12 weeks after natural infection
    • Immediately before vaccination
    • 1 to 2 weeks after vaccination

RESULTS:

• 18 serum samples from 6 healthcare workers
• The sample obtained at the first time point (1 to 12 weeks after infection)
  • Had neutralizing activity against
    • The original virus: geometric mean titer 456
    • B.1.1.7 (UK): 256
    • P.1 (Brazil): 71
  • Had no neutralizing activity against
    • B.1.351 (South Africa): geometric mean titer 8
• Immediately before BNT162b2 vaccination, titers were lower against all virus variants
  • Original virus: geometric mean titer 81
  • B.1.1.7 (UK): 40
  • P.1 (Brazil): 36
  • B.1.351 (South Africa): 7
• 1 to 2 weeks after vaccination, titers were high against all virus variants
  • Original virus: geometric mean titer 9195
  • B.1.1.7 (UK): 8192
  • P.1 (Brazil): 2896
  • B.1.351 (South Africa): 1625

CONCLUSION:

• After one dose of the BNT162b2, people who had previously been infected with the original SARS-CoV-2 showed high neutralizing activity against the UK, South Africa and Brazil variants
• The authors conclude

This highlights the importance of vaccination even in previously infected patients, given the added benefit of an increased antibody response to the variants tested

Learn More – Primary Sources:

Neutralizing Response against Variants after SARS-CoV-2 Infection and One Dose of BNT162b2